History and Explanation of the TMDL Policy/Program
Protecting and conserving water resources throughout the United States has been a concern and priority since the environmental movement and creation of the Environmental Protection Agency in 1970. In 1972 the Clean Water Act (amendments to the Federal Water Pollution Control Act) brought about many new policies to regulate water bodies across the country (Younos, 2005). Since then significant progress ensued with regards to regulating point sources, due to the National Pollution Discharge Elimination System (NPDES) permit program, under section 402 of the CWA. This permit process applies technology based controls to limit the discharge of pollutants from point sources (Lebowitz, 2001). Once a state regulatory agency has developed an approved NPDES program, it determines the amounts of certain pollutants that may be discharged by a particular discharger, from a specific source, and issues a permit that lists the requirements and limitations that discharger must follow for operation. If a state does not have an approved NPDES program, the U.S. EPA runs the permit process (Lebowitz, 2001).
The CWA also required the adoption of water quality standards for each state. The purpose of these standards is to identify the designated uses of each water body within the state, and to establish the water quality criteria based upon these uses. These standards are composed of chemical and biological components the water body must maintain for it to still meet its designated use (Lebowitz, 2001). The value of the waters for public water supplies, fish and wildlife use, recreational purposes, agricultural, industrial, and navigational use are all details that are taken into consideration. Any NPDES permit must limit the discharge of pollutants so that the water quality standards are met (Lebowitz, 2001). These standards are undeniably the key to protecting and preserving the quality of our country's water bodies. They set the baseline for determining whether regulatory efforts to preserve a water body's quality have been successful or not (U.S. EPA, 2003).
Perhaps the most important policy the CWA enacted is the Total Maximum Daily Load (TMDL) policy and program. Section 303(d) of the CWA states that each state, territory, and authorized tribe are required to develop lists of impaired water bodies, within their jurisdiction, and submit these lists to the U.S. EPA. An impaired water body is one that has failed to meet its designated use, as set by the states water quality standards (U.S. EPA, 1999). Each of these impaired water bodies requires an established TMDL. A TMDL, by definition, represents the maximum input, or load, of a certain pollutant from all the contributing point and/or nonpoint sources that may be added to a water body on a daily basis, while still allowing that water body to maintain or achieve its designated use (Lebowitz, 2001).
This policy lay dormant for some time, mostly due to confusion and the failure of the U.S. EPA to adequately address TMDLs in the basin planning process. The U.S. EPA failed to identify impaired waters as directed, and very few states were compiling lists of these impaired water bodies within their boundaries (Younos, 2005). Extensive litigation in the 1980s and 1990s began to unfold, and subsequently states started making lists of impaired waters and schedules for establishing the first TMDLs. These first few TMDLs only focused on point sources, such as reexamining permits through the NPDES process. By the early 1990s over 20,000 water bodies were identified as impaired and it was clear the U.S. EPA TMDL program needed some revamping (Younos, 2005).
The late 1990s and early 2000s brought about new policy and change focused on the TMDL program. In 1996 the Watershed Protection Approach Framework was adopted by the U.S. EPA as its framework for environmental management. This approach went hand in hand with the TMDL program, as it understood the complexity of nonpoint sources and the importance of stakeholder involvement to ensuring environmental regulations (Lebowitz, 2001). The following year the U.S. EPA also created the Federal Advisory Committee Act to provide states and regions some guidance for TMDL creation and implementation strategies. This committee tried to reach consensus among states, environmental groups, and point and potential nonpoint source dischargers for procedures of implementing the TMDL requirements under section 303(d) (Lebowitz, 2001). The main argument the committee faced, and one that continues today, is whether nonpoint source dischargers, like agricultural and timber industries, should be included in the TMDL regulations or not. These industries argue that nonpoint sources are already being controlled under section 319 of the CWA, which requires states to develop nonpoint source management programs for controlling pollution added from nonpoint sources to a water body identified as impaired. These groups claim that best management practices are enough and specific limits on pollutants are uncalled for.
In 1998 the Clean Water Action Plan (CWAP) was announced by President Clinton to address the lack of progress in meeting the goals of the CWA. The CWAP was the final push to create new rule changes for water quality management areas that were lacking. This plan geared federal, state, and local agencies and organizations to the watershed management approach, and therefore focused on implementing the TMDL program (Lebowitz, 2001). After the creation and discussion of proposals in 1999 regarding new TMDL rules, the administrator of the U.S. EPA signed these new rules on Jul. 1, 2000, titled “The Final Rule”. The U.S. EPA stated these new rules were needed to strengthen the TMDL program, and to finally tackle the significant water quality problems that persist more than 25 years after the enactment of the CWA. These final revised rules build on the current TMDL regulatory program by adding needed details, many specific required steps, as well as schedules (Copeland, 2000). Though these new rules were stopped from being enacted by Congress, the draft of these rules provided much more clarity and a framework for states to follow.
Each state has its own TMDL program which can differ greatly from state to state due to resources, staff, funding, and the overall approach followed. Each program is comprised of individual TMDLs for each water body. These TMDLs are large documents that include numerous details to run and ultimately complete the project (U.S. EPA, 1999). The back bones of these documents are the actual TMDLs for each pollutant that is impairing the water body. This states the amount of the pollutant the water body can receive and still meet its water quality standards. These pollutants are then linked to point or nonpoint sources. Allocations are calculated for each pollutant for each source, based on the TMDL. Wasteload allocations refer to point sources, while load allocations refer to nonpoint sources (FIG. 1, U.S. EPA, 1999).
Eleven different elements are required to be included in a state TMDL: 1) impaired water body name and geographic location; 2) identification of the pollutant and applicable water quality standard; 3) amount of the pollutant load that may be present in the water body and still meet its water quality standards; 4) the amount of the pollutant load present in the water body that exceeds the total maximum daily load; 5) identification of the source categories, subcategories, or individual sources of the pollutant for which wasteload and load allocations are being established; 6) wasteload allocations; 7) load allocations; 8) a margin of safety that allows for uncertainty; 9) consideration of seasonal variations; 10) allowance for future growth which may account for reasonably foreseeable pollutant load increases; 11) an implementation plan; (U.S. EPA, 1999).
Problems with TMDL Program and Process
The sampling procedure and analysis process are very important in determining correct and viable maximum loads, to ensure they are not understated or overstated, and that they properly represent the entire water body. The ability to capture water quality data sets over the surface of entire water bodies has been a goal of surface water professionals for decades. The monitoring process for these stated pollutants and their capacities is an essential part of ensuring that the water body will eventually be removed from the impaired list, and will once again meet its water quality standards. Several different studies examining implementation success of TMDLs have pointed out that monitoring is a factor that makes or breaks implementation success (Benham & Zeckoski, 2007; Furtak & Norton, 2009; Virginia Tech, 2006; Younos, 2005). In one study it was stated that one of the two most negative factors affecting TMDL implementation success is a lack of data, due to the failure to properly monitor the impaired water body (Benham & Zeckoski, 2007).
Currently, sampling procedures among different states vary from agency to agency due to the amount of available resources such as staff and funding (Younos, 2005). States that are short staffed or lack funding are not able to enforce a consistent measurement and monitoring routine. Therefore, these impaired water bodies lack the adequate amount of sample sizes and monthly monitoring visits. The state of Ohio is a great example of a state agency lacking adequate funding. The U.S. EPA has provided the agency with a small grant to look at up to 12 lakes per year, over a two year period. When these lakes are sampled, the normal procedure is to collect water samples from one to two locations in the deepest portion of the lake (Merchant, 2010). This current sampling routine and procedure is not enough to confidently consider if a water body has failed to meet its water quality standards, and to accurately provide a sufficient amount of monitoring to supervise the water bodies overall health.
Providing data sets without considerable data gaps is extremely difficult using field sampling methodology. These conventional methods for detecting phosphate concentrations and other water quality markers are time-consuming and expensive, especially for multi-seasonal monitoring over large-scale areas. Further, convention testing methods do not allow mapping of phosphate concentrations and other water quality markers in the past, which is important for understanding sources of phosphate contamination and other water quality markers.
Characterizing the chemistry of a surface water body is often limited by: large surface areas, time constraints, available manpower, access to sample collection points, and project cost or budget constraints. These limitations typically result in the gathering of grab samples that are not sufficient to statistically represent the average chemical characteristics of the entire surface water area being studied. Consequently, these data gaps may lead to the compilation of misleading, overly conservative or inadequate evaluations with respect to monitoring and remedial efforts towards improving water quality.
Currently, surface water data can be collected in situ using field sampling methods. Data is typically collected by a field technician who may analyze water samples using field instruments, portable laboratory kits or through the process of sending samples into a laboratory. Deciding what method to use depends upon the goals of specific projects and data quality requirements. Costs for field sampling include labor, equipment, fuel, laboratory and reporting fees. These costs are typically in the hundreds of United States dollars per sample.
Additionally, in situ testing of remote bodies of water or those that are otherwise difficult to access can be costly and time consuming to even obtain the sample. The present invention allows mapping of these bodies of water without the time, effort, and expense of traveling to such bodies of water.
In 2002 the U.S. EPA stated that sample size is an important element of data quality, and sample sizes are important for statistical tests in detecting Water Quality Standard exceedances (U.S. EPA, 2002). In general a sample size of 30 or more is accurate, while smaller sample sizes are inaccurate and have a low probability of detecting any exceedances (U.S. EPA, 2002). Any decisions based on very small data sets should only be made when there is overwhelming evidence of a specific impairment. The National Lake Assessment, completed by the U.S. EPA in 2007, had crews collect one sample at a single station in the deepest point of the lake, and at some sites had an additional ten collection stations around the perimeter of the lake (U.S. EPA, 2009). As the U.S. EPA stated in 2002, taking one sample or even an additional ten samples is not accurate enough to truly represent the overall quality of the entire water body, regardless of how many parameters are measured from those few samples.
As of Jan. 12, 2012 there are a total of 41,266 impaired water bodies throughout the country in need of a TMDL. There are a total of 46,817 TMDLs that have been approved by the U.S. EPA, that are now in the implementation and monitoring phase (U.S. EPA, 2012). The amount of TMDLs focused on impairments by nutrients is 6,893 (3rd most common impairment), while 5,249 nutrient TMDLs have been already been created (USEPA, 2012). The state of California alone has 1,189 approved TMDLs that are now in the implementation and monitoring phase (USEPA, 2012). These numbers clearly indicate that the TMDL program needs assistance, in both the creation and monitoring phases. Satellite remote sensing can provide large amounts of data to help define impairments, design the total maximum daily loads, and efficiently monitor these water bodies.
Satellite Remote Sensing
Over the past decade, satellite remote sensing data has proven to be an essential tool in several different aspects of environmental science. Remote sensing has been shown to aid greatly in analyzing and monitoring bodies of water and assessing their quality. Several different studies have had success at measuring and monitoring different water quality parameters, such as chlorophyll-α and turbidity (Cooper & Ritchie, 2001; Govender, et. al., 2006; Hadjimitsis & Clayton, 2011). Algorithms have been developed that effectively measure various aqueous chemical constituents, completely from space acquired data that has a dense net of data points. The data from these algorithms have high statistical correlations with water measurements taken from within the water body (Vincent, 2010). Satellites provide temporal and spatial data for surface water quality parameters that is not possible from in situ measurements (Cooper & Ritchie, 2001). LANDSAT TM satellite data is free and can be received as quickly as a few hours to a few days after satellite overpass. These satellite images have a 30 meter spatial resolution that produces five measurement points per acre: if a body of water is 3,000 acres in size, then there will be 15,000 measurements for each satellite pass over that body of water (Vincent, 1997).
The incorporation of satellite monitoring into the TMDL process is a low-cost and effective way to obtain a much greater magnitude of accurate data for a particular water body, as compared to manual sample collection procedures. For example, satellite remote sensing gives up to 5,000 times more measurements for a 1,000-acre lake. Satellite monitoring can also be performed on a monthly basis, without having requiring the funding or staff to collect water samples. Though satellite water quality algorithms have currently been developed for only a few water quality parameters, more will be developed in time. Also, some of the current satellite water quality algorithms may also prove to have a strong correlation with other parameters presently without a satellite algorithm. The technology and capability to develop such algorithms are sure to increase in the future, with the development and launching of new satellites designed for this purpose.
Remote sensing of entire water body highlights areas of significant impact so the user can focus monitoring and remedial efforts at those locations. In many instances, this results in reducing costs for monitoring or physical/chemical treatments because the entire water body does not have to be monitored or chemicals may not need to be applied to an entire body of water. This focused approach to remediation results in a level of detail not possible using evaluations from single grab samples. Thus, there is a need for an efficient and cost effective method for obtaining the comprehensive data packages to supplement current monitoring and modeling programs for bodies of water.
Devices and techniques disclosed in U.S. Pat. No. 7,132,254, U.S. patent application Ser. No. 10/762,952, and U.S. patent application Ser. No. 13/284,145 relating to remote sensing may be adapted to the present invention and are hereby incorporated by reference.
The present invention is able to determine the total phosphate concentration for every one-fifth of an acre in a surface body of water within a few seconds. As noted previously, one measurement in a lake by current in situ methods costs approximately $600 dollars per data point. If a measurement were taken for a 1,000 acre lake, 5,000 measurements would be needed to match the present invention. The cost to do so would be approximately $1.5 million. The present invention obtains the same results for only about $0.10 to $2.00 per acre, which would total $100-$2000 for a 1,000 acre lake.
Excessive nutrient input into water bodies accounts for one of the most common type of impairment, and currently 6,893 water bodies are in need of a nutrient TMDL, while 5,249 require the monitoring of nutrient impairments (U.S. EPA, 2012). Many of the studies that have resulted in success with various algorithms to monitor water bodies are mainly parameters that are measured and monitored for nutrient TMDLs, as nutrients are normally the impairments. Therefore, it is evident that this could especially be an area that satellite remote sensing could improve.
One reason it is important to map and detect phosphate concentrations in bodies of water is because elevated phosphate levels are one of the root causes of increased blooms of these harmful algae such as cyanobacteria. Through mapping past phosphate levels, it is possible to track when and how phosphate enters a body of water.
An important factor to note concerning nutrient TMDLs are the resulting algal blooms and the parameters chosen to monitor this degradation. After excessive nutrient inputs, massive blooms of algae often follow, including Harmful Algal Blooms (HAB) that contain cyanobacteria. Different strains of cyanobacteria create dangerous toxins, which are harmful to animals and humans (Ingraham, 2000). Where a nutrient impairment exists, and algal blooms are present, it is extremely important to determine whether these blooms contain cyanobacteria (Gons, 2005). Many water bodies used for recreational purposes are being closed to the public due to these blooms and the dangers they present human health. While chlorophyll-α is currently the most widely used parameter used to monitor algal blooms, a pigment known as phycocyanin should be established as another parameter used to monitor lakes for cyanobacteria. Chlorophyll-α is contained by a majority of all land plants and algae, while phycocyanin is found almost uniquely in cyanobacteria, and in a few other algae species (Ingraham, 2000). Previous studies have created algorithms to accurately measure and monitor the more nearly unique cynobacterial pigment, phycocyanin, for the regulation of cyanobacteria blooms (Vincent et al., 2004). More attention should be drawn to this parameter, and phycocyanin algorithms for both low blooms and high blooms of cyanobacteria will be applied in this study.
The presented embodiments show how remote sensing applications can improve the TMDL process in two main areas: the original measurement process to determine the impairments and maximum loads of the subject water body, and the subsequent monitoring process, to determine how successfully the impairments have been mitigated.